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Super drivers and electric cars

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The average American driver travels about 13,400 miles a year. The top 10% of drivers average about 40,200 miles a year and account for 35% of the nation’s gasoline use from private light-duty vehicles, meaning cars, SUVs, pickup trucks, vans, and minivans.  Those 21 million Americans alone burn more gasoline than is burned each year in Brazil, Canada, and Russia combined.

These super drivers often live in rural areas and small towns, drive an average of 116 miles each weekday, and typically own vehicles that are larger and less fuel efficient.  Many have long commutes to work because they were pushed out of cities by rising housing prices.  Some are tradespeople who travel from site to site all day in their jobs. 

Given the disproportionate amount of gasoline usage by this small segment of the population, the key to cutting vehicle emissions by adopting electric vehicles may rest with super drivers.  And so far, not many of them have made the transition.

A report by the environmental nonprofit group Coltura contends that getting super drivers to switch to electric cars would lead to a much faster reduction in emissions.

The range of most recent electric cars is sufficient for most super drivers.  The obstacles remaining include availability of convenient charging stations, but that is changing.  Finding the right vehicle might also be a problem, but electric pickup trucks and large SUVs are entering the market. 

The transition to electric vehicles is important for society, and the most active drivers need to take part in it.

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Are You a Super Driver? Some States Want to Help You Go Electric.

Photo, posted January 9, 2025, courtesy of Phillip Pessar via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

New Orleans is sinking

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As climate change accelerates, rising sea levels are putting coastal communities at greater risk of flooding and storm surge. Driven by melting glaciers and warming oceans, global sea levels are rising at an increasing rate. For low-lying cities like New Orleans, even small increases can have serious consequences. And that risk is compounded by another factor: the land itself is sinking.

Much of New Orleans already sits at or below sea level, and parts of the city and its surrounding wetlands are gradually sinking. While most of the city remains stable, a new study by researchers from Tulane University suggests that sections of the region’s $15 billion post-Katrina flood protection system may require ongoing upgrades to keep pace with long-term subsidence.

The study, recently published in the journal Science Advances, used satellite data to track changes in ground elevation across Greater New Orleans between 2002-2020.  The researchers found that some areas – including neighborhoods, wetlands, and even concrete floodwalls – are sinking by more than an inch each year. In some spots, the land is dropping by nearly two inches annually.

Alarmingly, some of the concrete floodwalls and levees built to protect the city after Hurricane Katrina are themselves sinking. In a few cases, they are losing elevation faster than sea levels are rising, reducing their capacity to block storm surges.

The study highlights how satellite monitoring can play a critical role in guiding infrastructure maintenance and urban planning – not just in New Orleans – but in vulnerable coastal cities around the world.

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Vertical land motion in Greater New Orleans: Insights into underlying drivers and impact to flood protection infrastructure

Photo, posted September 22, 2010, courtesy of U.S. Army Corps of Engineers via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Deconstructing buildings

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An estimated 30 million tons of wood waste from construction and demolition in the U.S. ends up in landfills each year.  A growing number of cities have launched initiatives to reuse the wood instead.  It is a strategy to reduce carbon emissions, cut waste, and shift towards a circular economy.

For a long time, salvaged wood was a niche pursuit by people who valued the fine grain and enduring quality of older wood.  Reclaimed old-growth lumber offers character and strength.  These people pursued construction that uses wood with a story – timber recovered from historic structures, collapsing barns, and other demolished buildings.

Now, there are multiple companies in the business of salvaging wood from buildings.  Cities and businesses are embracing the use of reclaimed materials.   Ordinances in cities like Portland, Oregon, Boulder, Colorado, and San Antonio, Texas require older buildings to be taken apart for repurposing their materials.  Palo Alto, California has banned demolition completely. 

Portland was the first U.S. city to require old residential homes to be deconstructed.  After a decade, contractors have deconstructed more than 650 homes in the city, salvaging 2,000 tons of reusable wood.

Using reclaimed wood in local buildings stores carbon and reduces emissions by avoiding the need to cut new trees, process materials, and ship them long distances.

Deconstructing buildings is not a widely available skill.  Contractors have to be trained on how to dismantle buildings piece by piece.  But there is now a national registry of deconstruction trainers and a network of practitioners.

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Deconstructing Buildings: The Quest for New Life for Old Wood

Photo, posted May 16, 2018, courtesy of Alexandre Prevot via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Solutions for cleaner air

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Air pollution is a problem for most of the world’s cities.  Many cities in India and China continue to face major public health crises due to their polluted air.  American cities also don’t escape from polluted air.  Californian cities still struggle with smog despite decades of effort to reduce it.  But one major city that has waged a successful battle against air pollution is Paris, France.

Over the past 20 years, Paris has transformed its air by trading automobile roads for bike lanes, adding green spaces, and eliminating 50,000 parking spaces.

According to independent air quality tracking, levels of fine particulate matter in Paris have decreased 55% since 2005 and nitrogen dioxide levels have fallen 50%.  A combination of regulations and public policies including steps to limit traffic and ban the most polluting vehicles have produced these results. 

Despite pushback from various sources such as car owners’ associations, suburban commuters, and right-leaning politicians, Parisians have continued to pursue cleaner air policies.  In April, Parisians voted to turn an additional 500 streets over to pedestrians.  Last year, Paris sharply increased parking fees for SUVs, forcing drivers to pay three times more than they would for smaller cars. 

Ambitious policymaking can directly improve health in large cities.  As one former advisor to the city explains, the French capital has developed “an urban policy based on well-being.”

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Paris said au revoir to cars. Air pollution maps reveal a dramatic change.

Photo, posted June 3, 2018, courtesy of Francisco Anzola via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Our cities are sinking

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A new study by the Columbia University Climate School has found that all of the 28 most populous cities in the United States are sinking to some extent.  This phenomenon of subsidence is not just taking place in cities on the coast, where relative sea level is an issue, but also in cities in the interior.

The primary cause of subsidence is large-scale groundwater extraction for human use.  When water is withdrawn from aquifers made up of fine-grained sediments, the pore spaces formerly occupied by water can eventually collapse, leading to compaction below and sinkage at the surface.

The fastest sinking city in the US is Houston, with more than 40% of its area subsiding more than 5 millimeters a year and 12% sinking at twice that rate.  Some local spots are going down as much as 5 centimeters a year.   These seem like very small numbers but the fact that the subsidence is often not uniform across an urban area means that there are stresses to building foundations and other infrastructure.  Parts of Las Vegas, Washington D.C., and San Francisco have particularly fast sinking zones.

There are other causes of subsidence.  In Texas, pumping of oil and gas adds to the phenomenon.  A 2023 study found that New York City’s more than one million buildings are pressing down on the Earth so hard that they may be contributing to the city’s ongoing subsidence.  About 1% of the total area of the country’s 28 largest cities faces some danger from uneven subsidence.

Overall, some 34 million Americans live in cities affected by subsidence.  Global cities facing especially rapid subsidence include Jakarta, Venice, and here in the U.S., New Orleans.

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All of the Biggest U.S. Cities Are Sinking

Photo, posted December 27, 2012, courtesy of Katie Haugland Bowen via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Living in a warming world

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As global temperatures rise due to increased greenhouse gas emissions, communities around the world face more frequent and intense heatwaves, droughts, and extreme weather events. These growing climate pressures not only strain infrastructure and natural resources, but also play a critical role in shaping where people live. 

Recent projections from the First Street Foundation, which analyzes climate risks across the United States, highlight just how significant these shifts could be. In Sacramento County, California, rising flood risks, declining air quality, and soaring insurance costs could lead to a population decline of up to 28% by 2055. The risk assessment also projects that Monmouth and Ocean counties in New Jersey could each lose more than 30% of their populations. And Fresno County, California, could see nearly half of its residents relocate due to mounting climate-related pressures.

Urban areas like cities, towns, and suburbs are particularly vulnerable to the impacts of climate change.  Cities become significantly hotter due to the abundance of heat-absorbing surfaces and lack of green spaces, which intensifies heatwaves, worsens conditions for vulnerable populations, and may ultimately force some people to move.

Addressing these challenges requires a combination of climate solutions focused on both mitigation and adaptation. Solutions like expanding green infrastructure with urban parks and green roofs, and promoting sustainable development through energy-efficient buildings and transit-friendly design could all play a vital role in strengthening climate resilience.

As the planet warms, where we live – and how we live there – is rapidly being redefined.

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The 12th National Risk Assessment

Solar on farmland

Photo, posted May 15, 2013, courtesy of Germán Poo-Caamaño via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Americans breathe unhealthy air

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According to the American Lung Association’s annual State of the Air report, at least 156 million Americans – 46% of the population – live with unsafe levels of ozone, particulate pollution, or both.

The report analyzed ozone and particulate pollution levels between 2021 and 2023, during which the worst wildfire season on record took place in Canada.  The report ranked pollution levels in counties and cities across the country on a grading scale from A to F.  At least 156 million people live with air that got the poorest grade of F for at least one of three pollutants.   At least 42 million people live in counties that failed all three pollutant standards measured.

While the report attempts to provide a complete picture of air quality around the country, about two-thirds of counties lack air quality monitoring for ozone or particulate pollution. 

The wildfires in Canada are responsible for much of the increase in air pollution in the past several years.  However, climate projections suggest that the conditions that fueled those fires are likely to become increasingly common.

Air quality standards in the United States have generally been improving since the Clean Air Act was enacted by Congress in 1970.  Since that time, levels of key pollutants have dropped by nearly 80%.  But millions of Americans are still breathing polluted air, leading to both acute and chronic health conditions.

Plans by the Trump administration to loosen environmental regulations and cut funding for air quality research are likely to only make matters worse.

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Almost Half of Americans Breathe Unhealthy Air, Report Finds

Photo, posted June 8, 2023, courtesy of Anthony Quintano via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Bees and urban wildflowers

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Post-industrial cities often have large numbers of vacant lots, left behind as people have moved out of the area.  Local residents are often tempted to plant wildflowers to make these deserted spaces more attractive. 

Wildflowers are an important food source for bees.  Pollinators like bees play a vital role in food production and attracting them with food sources is a good idea.  However, a study by researchers at the University of Cambridge in the UK found that there are dangers associated with planting wildflowers in some urban settings.

Wildflowers growing on land previously used for buildings and factories can accumulate lead, arsenic, and other metal contaminants from the soil.  These metals have previously been shown to damage the health of pollinators that ingest the metals in the nectar as they feed.

The Cambridge study was carried out in Cleveland, Ohio, which has nearly 34,000 vacant lots.  Cleveland was previously the site of iron and steel production, oil refining, and car manufacturing.  The researchers tested the nectar from flowering plants growing on disused land throughout the city.  Lead was the contaminant found in the highest concentrations.  They also found that different species of plants accumulate different amounts and different types of metals.

The goal of the study was not to discourage the planting of wildflowers in towns and cities.  It is to highlight the importance of growing the right species of wildflowers as well as to encourage testing soils for metals before planting wildflowers and to clean up pollution.  Wildflowers are important for pollinators, but it is also important that they don’t contribute to the decline of pollinator populations that has already been happening for a number of reasons.

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Growing wildflowers on disused urban land can damage bee health

Photo, posted August 26, 2012, courtesy of RJP via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Native plants and road salt pollution

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Applying salt to roadways lowers the freezing point of water and prevents slippery surfaces, which makes it safer for people to drive in wintry conditions.  In the U.S., more than 22 million tons of road salt is spread every year. 

But road salt harms infrastructure and the environment.   In fact, road salt damages cars and metal infrastructure by accelerating rust and corrosion.  Road salt can also leach into soil and waterways, disrupting ecosystems, degrading soil, contaminating water, and damaging vegetation. 

In cities and towns, road salts often wash into stormwater systems, posing health concerns and challenges for infrastructure.

A new study led by researchers from Virginia Tech looked at how salt affects plants and whether certain plants could mitigate salt pollution. The research team studied stormwater detention basins in Northern Virginia, examining the impacts of road salt on plants, soils, and water quality in green infrastructure systems.

The findings, which were recently published in the journal Science of the Total Environment, found that the amount of salt present in green infrastructure systems does reach levels that threaten plant communities.  However, the researchers found that relying on salt-tolerant plants for mitigation is unlikely to be effective because they simply don’t take in enough salt.

Certain plants, particularly cattails, absorbed substantial amounts of salt.  But even in a basin densely planted with salt-tolerant cattails, only up to 6% of the road salt applied during winter could be removed. 

Plants alone cannot solve our salt pollution problem.

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Researcher studies the power of native plants to combat road salt pollution

Photo, posted January 22, 2025, courtesy of the City of Greenville, North Carolina via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Wrong trees in the wrong places

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Temperatures in cities are rising around the world and urban heat stress is already a major problem.  Extensive surfaces of man-made materials absorb the sun’s energy, and lead to temperatures well above those in the surrounding countryside.  This is known as the urban heat island effect, and it can lead to greater energy use, higher air pollution levels, and a greater risk of heat-related illnesses, as well as death. 

Some cities have already started implementing mitigation strategies, with tree planting prominent among them.  Planting trees can cool the climate by absorbing carbon dioxide, providing shade, and releasing water vapor, which lowers air and surface temperatures. 

However, while trees can cool cities significantly during the day, new research from the University of Cambridge in the U.K. shows that tree canopies can also trap heat and raise temperatures at night. 

According to the study, which was recently published in the journal Communications Earth & Environment, planting the wrong species or the wrong combination of trees in suboptimal locations or arrangements can limit their benefits.

The researchers found that in temperate climates, trees can cool cities by up to 6°C during the day but can increase nighttime temperatures by 1.5°C.  Cities with open layouts in temperate and tropical climates benefit from a mix of evergreen and deciduous trees, enhancing cooling by 0.5°C more than in cities with only deciduous or evergreen trees. 

The researchers hope their findings will help urban planners choose the best combinations of trees and planting locations to combat urban heat stress.

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Wrong trees in the wrong place can make cities hotter at night, study reveals

Photo, posted October 29, 2017, courtesy of Lars Plougmann via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Slow-moving landslides

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Landslides are mass movements of rock, earth, or debris down a slope.  They can be initiated by rainfall, snowmelt, changes in water level, erosion by streams, earthquakes, volcanic activity, or by various human activities.  Most landslides we hear about are sudden events that can cause all sorts of calamities.  But not all landslides are rapid occurrences.  There are also slow-moving landslides.

A new study by the University of Potsdam in Germany has found that as urban centers in mountainous regions grow, more people are building homes on steeper slopes prone to slow-moving landslides.  Slow-moving landslides can move as little as one millimeter a year and up to as much as three meters per year.  Locations with slow-moving landslides can seem safe to settle on; in some cases, the movement itself can be inconspicuous or even completely undetected.

Slow slides can gradually produce damage in houses and other infrastructure and there can also be sudden acceleration from heavy rain or other influences.

The study compiled a new database of nearly 8,000 slow-moving landslides with areas of at least 25 acres located in regions classified as “mountain risk.”  Of the landslides documented, 563 are inhabited by hundreds of thousands of people.  The densest settlements on slow-moving landslides are in northwestern South America and southeastern Africa. 

In all regions of the study, urban center expansion was associated with an increase in exposure to slow-moving landslides.  As cities expand in mountainous areas, people are moving into unsafe areas, but poorer populations may have few other options.

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Slow-moving landslides a growing, but ignored, threat to mountain communities

Photo, posted March 4, 2015, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Cities and rainwater

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Cities across the country are grappling with the problem that bigger, more frequent rainstorms occurring as a result of climate change are overtaxing the systems put in place to handle stormwater.  Cities use a combination of so-called green infrastructure – such as rain gardens and porous pavements – and traditional gray infrastructure, such as pipes, tunnels, and pump stations.

In 2011, Philadelphia drew national attention for its Green City, Clean Waters program that was designed to manage the increasing amount of storm water using mostly green infrastructure.  Thirteen years later, the city is experiencing billions of gallons of polluted stormwater overflowing its sewage outfall pipes each year.  Green infrastructure is cheaper and faster to build, but it is not coping with increasing rainfall.

About 700 U.S. municipalities, mostly in the Northeast and around the Great Lakes, rely on these combined sewer systems.  Based on updated climate projections, many are having to greatly increase gray infrastructure projects that include concrete holding tanks, tunnels, and pipes that can divert and hold onto flows until the rain stops, and water treatment plants can recover.  These projects can take decades to implement and cost billions of dollars.

All across the country, cities are going to need to bite the bullet and make large-scale investments in conventional sewage infrastructure and repairs to stop billions of gallons of raw sewage from running into rivers.  The increased storms present a daunting challenge for America’s cities.

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Faced With Heavier Rains, Cities Scramble to Control Polluted Runoff

Photo, posted August 29, 2011, courtesy of Reggie via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Cooling cities

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As the climate warms, city dwellers tend to suffer from extreme heat more than people in rural areas because of the urban heat island effect. Extensive surfaces of man-made materials like concrete, asphalt, and brick absorb the sun’s energy and lead to temperatures well above those in the surrounding countryside.

Cities can take countermeasures that include creating urban green spaces full of plants that cool the surrounding air and the use of cool roofs that reflect the sun’s energy back into space.  Local governments in many cities provide incentives for planting more trees.  But more could be accomplished by encouraging the use of cool roofs.

The heat island effect has been well-known for a long time, but scientists are only recently learning what interventions are most effective. A recent study modeled two days of extreme heat in London in 2018 and compared the potential effects of cool roofs, green roofs, roof-top solar panels, and ground level vegetation. They found that cool roofs are the most effective way to lower temperatures and would have reduced London temperatures by 2 degrees on average and as much as 3.6 degrees in some places.

Cool roofs are created by swapping out dark, heat-absorbing roofing materials with reflective materials or simply by painting roofs white. Los Angeles is the first major city to require that all new residential construction includes a cool roof. 

Apart from the effectiveness of passive cooling techniques, using them also reduces the reliance upon air conditioning to protect people from heat.  Air conditioners themselves contribute considerable amounts of heat to urban environments.

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The surprisingly simple way cities could save people from extreme heat

Photo, posted February 21, 2024, courtesy of Warren LeMay via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Floating cities

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About 40% of the world‘s population lives in coastal regions.  People really like ocean-front property.  But worldwide, rising sea levels mean that more and more people want to live on land that may someday be swallowed up by the sea.

One possible solution to the problem is to build cities on top of the water.  It sounds pretty futuristic and impractical, but it is starting to happen.  There have long been floating communities in places like the Netherlands, but these are for the most part clusters of houseboats moored close together.

But there are far more ambitious projects underway.  The Maldives Floating City, already under construction, will eventually have 5,000 houses located in a lagoon that is a 15-minute boat ride from the capital city of Male.  The housing units will be tethered to the lagoon floor and linked together. 

A new project, located off Busan, South Korea, will combine high and low technology to create a large-scale, on-water town, that can house more than 10,000 people.

The town will be built on enormous concrete platforms suspended on the water.  The platforms float because they are rounded hexagonal boxes that are buoyed up by Archimedes’’ principle.  They can’t sink.  Such structures will attract marine life, providing places for oysters and mussels, for example, to grow. 

The initial development will cover 15 acres and the infrastructure will handle power, water, waste, and even some food.  The goal is even to produce enough energy to provide some to the nearby community.  A bridge will link the community to the land.

The project is scheduled to be completed in 2028.  Future expansion could end up housing 150,000 people.

Floating cities could soon no longer be exotic or futuristic.

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Are Floating Cities the Solution to Rising Seas?

Photo, posted June 5, 2012, courtesy of Raymond Bucko via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Natural solutions for coastal defense

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Protecting coastal cities and towns from the dangers of tsunamis, storm surges, and sea-level rise has become an ever-increasing challenge.  There are so-called hard coastal defenses as well as nature-based solutions.  A new study by the University of Tokyo has found that combining the two types of defenses may be the most effective way to protect, support, and enrich coastal communities.

Sea walls, dikes, dams, and breakwaters are the traditional hard measures.  They are popular and have proven track records but are facing challenges to keep pace with increasing climate risks.  They are expensive to build and require continuous upgrades and repairs.  While they do provide protection from many disaster risks, they also can cause significant disruption to coastal ecosystems as well as to coastal communities.

Nature-based coastal defenses include such things as mangroves and coral reefs.  So-called soft measures involve restoring, rehabilitating, reforesting, and nourishing natural ecosystems that protect coastal areas.

The Tokyo researchers analyzed the defense strategies in terms of risk reduction, climate change mitigation, and cost-effectiveness over a 20-year period. The results of the study were that among all coastal defense options in lower-risk areas, hybrid measures provide the highest risk reduction and can harness the advantages of both hard and soft measures. 

The findings provide strong evidence for integrating nature-based components into coastal defenses, but these approaches have not yet been adequately tested in circumstances of extreme events and high-risk urgency.  Research in this area has important implications for policy makers, coastal planners, and communities looking to make evidence-based decisions.

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A natural touch for coastal defense

Photo, posted October 22, 2021, courtesy of Kevin Dooley via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The Colorado River crisis

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The Colorado River serves nearly 40 million people in seven U.S. states and Mexico.  It provides water for 5 million acres of farmland.  Increasing demand from growing populations, damming, diversion, and drought have been draining the Colorado at alarming rates.  This critical resource supports countless economies, communities, and ecologies stretching from the Rocky Mountains to the Gulf of California.  The Colorado River essentially has made the cities of Las Vegas, Los Angeles, Denver, and Phoenix possible.

How the water of the Colorado is distributed is determined by an agreement that is over 100 years old:  the Colorado River Compact.  It was made at a time when people thought there was more water than really was there.  And at the time, no one thought that the seven states would need to use the water they were allocated down to the last drop.

There have been various measures over the years to conserve water from the Colorado River, including the Colorado River Interim Guidelines in 2007.  Those guidelines will expire in 2026 and negotiations are beginning to take place among the many stakeholders scrambling for water rights.  Apart from the seven U.S. states and Mexico, there are 30 tribal nations involved.  Collaborative governance is complicated when it crosses multiple jurisdictions with their own laws and legal precedents.  The goal is to put in place a new agreement to protect the Colorado River.

Rapidly-growing populations in major cities, a 20-year megadrought, and historically low water levels in America’s two largest reservoirs have put enormous pressure on the Colorado River.  Creating a plan to protect the lifeblood of the American West is essential.

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Addressing the Colorado River crisis

Photo, posted June 18, 2022, courtesy of Jeff Hollett via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Major species turnover forecasted for North American cities

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Climate change affects animal species in many ways.  It induces habitat loss, disrupts migration and breeding patterns, threatens marine life, and facilitates an increased spread of disease.  It may also affect where animals can be found in the future. 

According to a new study led by researchers from the University of Toronto Mississauga and Apex Resource Management Solutions in Canada, climate change may dramatically affect the animal species observed in North American cities by the end of the century.

The researchers used species distribution data combined with machine learning to study the impact of human-caused climate change on more than 2,000 animal species historically found in the 60 most populous North American cities. 

According to the research team, changes in biodiversity are brewing for almost every city it studied by the year 2100.  In fact, cities with a rich history of biodiversity are predicted to have the largest declines and fewest gains in species. Cooler and wetter cities like Quebec, Ottawa, Winnipeg, Kansas City, and Omaha are expected to welcome the most new species.  Warmer cities with higher precipitation – like cities in coastal California – are projected to lose the most species. 

More than 95% of bird and insect species are predicted to experience a change in the number of cities they call home.  Canines, most amphibians, and aquatic birds are expected to experience the greatest losses.  Toads, turtles, mice and pelicans are projected to become more common overall. 

The researchers hope their findings will encourage more efforts to protect biodiversity.

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North American cities may see a major species turnover by the end of the century

Photo, posted September 29, 2013, courtesy of Jonathan Kriz via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

How to make cities cooler

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In cities, the air, surface, and soil temperatures are almost always warmer than in rural areas. This is known as the urban heat island effect.  Urban heat islands occur when cities replace natural land cover with dense concentrations of pavement, buildings, and other surfaces that absorb and retain heat.

Urban planners around the world have been researching ways to reduce the effects of heat in cities.  For example, trees, green roofs, and vegetation can help reduce urban heat island effects by shading building surfaces, deflecting radiation from the sun, and releasing moisture into the atmosphere.

A new study led by researchers from the University of Surrey in the U.K. has analyzed how well various green spaces and waterways are able to cool down cities.  The study, which was recently published in the journal The Innovation, found that wetlands, parks, and even botanical gardens are among the best ways to keep cities cool.   

In fact, the researchers found that botanical gardens can cool city air by a whopping 9°F during heatwaves on average.  Wetlands can cool city air by 8.5°F on average, followed by rain gardens at 8.1°F, green walls at 7.4°F, street trees at 6.8°F, city farms at 6.3°F, city parks at 5.8°F, and reservoirs and playgrounds at 5.2°F. 

The researchers also found that cities can unlock even greater benefits by connecting green spaces into green corridors.  Greening projects can also help remove carbon emissions and prevent flooding.

The research team hopes its findings will help urban planners design more resilient cities. 

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Wetlands, parks and even botanical gardens among the best ways to cool cities during heatwaves

Photo, posted April 25, 2022, courtesy of Catherine Poh Huay Tan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The East Coast is sinking

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Most of the world’s largest cities are located in coastal regions and coastal regions are on the front lines of the climate crisis.  Human populations continue to migrate towards low-elevation coastal areas at the same time that sea level rise is accelerating.  Coastal communities worldwide are increasingly vulnerable to the dangers of flooding and erosion.  With these hazards occupying a great deal of attention, there has been less attention paid to the dangers of land subsidence.

A recent study by researchers at Virginia Tech and the US Geological Survey using satellite data shows that parts of America’s east coast are sinking, and the culprit is the withdrawal of too much water from the aquifers beneath these coastal areas.

A series of overlapping aquifers extends all the way from New Jersey to Florida along the coast, providing a reliable source of water for drinking, irrigation, and industrial uses.  Even though these areas get regular rainfall, the deeper aquifers can take hundreds or even thousands of years to refill once water is pumped out.  Once water is removed, soils can compress and collapse, causing the land surface to sink.

Cities that were built on drained marshland or on fill soil are especially vulnerable to compaction. 

Seal level rise is slow, but it is insidious and continuous.  Add land subsidence to the mix and effects multiply.  Places like Boston, New York, Washington DC, Roanoke, Savannah, Jacksonville, and Miami, among others, all are increasingly vulnerable to these coastal hazards.  The combined effects of sea level rise and subsidence may even triple the prospects for flooding areas over the next few decades.

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As Aquifers Are Depleted, Areas Along The East Coast Of The US Are Sinking

Photo, posted August 7, 2015, courtesy of Tracy Robillard / NRCS Oregon via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Air pollution in India

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India is one of the world’s most polluted countries.  In fact, of the 30 cities with the worst air pollution around the globe, 21 of them can be found in India. 

India’s capital city, New Delhi, is the most polluted city in the world.  Concentrations of fine particulate matter (known as PM2.5) in Delhi, which is the name of the larger city that includes the capital New Delhi, are nearly 10 times greater than the World Health Organization guidelines. 

To reduce air pollution in Delhi, officials have focused on measures within the city limits, including boosting public transportation and regulating pollution from industry. 

But according to a review carried out by the University of Surrey and regional government officials in Delhi, the city will also need the help of its neighbors to tackle its killer smog problem.  Some of the pollution plaguing Delhi comes from rural areas in the region –  from things like crop burning, wood stoves, and power plants.  The review, which was part of a paper recently published in the journal Sustainable Horizons, also recommends drafting regional air quality plans, producing smog forecasts, and creating airshed councils to help improve coordination. 

Exposure to air pollution can cause all sorts of major health problems, including asthma, respiratory inflammation, as well as  jeopardize lung function, and even promote cancer.  Long-term exposure to PM2.5 is linked to premature death.  In fact, air pollution causes an estimated 670,000 deaths every year in India. 

Since air pollution doesn’t respect boundaries or borders, solutions require collaboration and the need to focus efforts more broadly in order to achieve emissions reduction goals. 

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Delhi smog: India’s cities must look beyond their limits to clean up air pollution

Photo, posted December 27, 2019, courtesy of Ninara via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

WAMC Northeast Public Radio

WAMC/Northeast Public Radio is a regional public radio network serving parts of seven northeastern states (more...)